P1727: EPIDEMIOLOGICAL TRENDS OF HAEMATOLOGICAL MALIGNANCIES IN BELGIUM 2004-2018: OLDER PATIENTS SHOWED THE GREATEST IMPROVED SURVIVAL OVER TIME
Authors: K. Henau, T. Tambuyzer, B. Van Gool, L. Van Eycken, H. A. Poirel
Journal: HemaSphere (2022)

Background: Haematological malignancies (HM) are common (11% of the total cancer burden in Belgium in 2018) and, at the same time, they represent a heterogeneous group of rare malignancies, which are distinguished by specific clinico-biological characteristics, behaviour and outcome. Aims: We aim to analyse in more depth the epidemiological trends of HM in Belgium over a recent 15-year period, with a particular focus on the impact of age at diagnosis on the incidence and the survival trends by type of HM. Methods: The Belgian Cancer Registry (BCR) is a population based national cancer registry, collecting data since incidence year 2004. We studied the 23 main HM types (see Figure 1), representing 98% of all HM cases (N = 92.202), diagnosed between 2004 and 2018. Patients follow-up was available until 01/07/2020. We estimated age-standardised (WSR) incidence, incidence trends (Average Annual Percentage Change or AAPC), projections up to 2025, 5- & 10-year relative survival (RS), conditional RS and RS trends for the 23 main types of HM. Results: During the period 2004-2018, the WSR incidence rates of HM increased in Belgium (AAPC: 1.2%) and mainly in the older population (70+), while they remain stable in children. The greatest increase is observed for BCR/ABL1-negative chronic myeloid neoplasms. The 10-yr RS varies by age group and HM type. ALL shows the greatest age variation, from >90% in children under age 10 to <20% in adults 70+. For each type of HM, outcome gets progressively worse with age. The greatest decrease in 5yr-RS with age is observed for aggressive HM, such as AML, ALL/LL and BL: from 67%, 90% and 97% respectively in children and adolescents (0-19 yr) to 2%, 12% and 16% in adults 80+, respectively. The 5-yr RS of all HM has increased over the 15 years with 5 percentage point (pp) from 64% in 2004-08 to 69% in 2014-18 (Table 1). The greatest improvement is seen in ALL (+14 pp), followed by IPD and HDCN (+11 pp). No clear improvement is observed for most myeloid neoplasms except CML. Analysis by age group reveals larger increases in survival over time. The most impressive increases are seen in the older patients (80+), with +45 pp in HL (from 21% in 2004-2008 to 66% in 2014-2018), followed by IPD (+33 pp), FL (+28 pp), CML (+16 pp), PMF (+13 pp), CLL/SLL (+12pp) and MCL (+11pp). A strong improvement (+22 pp) is also observed for ALL/LL in the 60-79 age group, even if the 5y-RS remains low (37% over the 2014-18period). Young adults (20-39 yr) with BL showed great improvement (+21%) with survival progressing towards the level seen in children. PNK/TCL and MDS showed the greatest increase (+14 pp and +13pp respectively) in adults (20-59 yr), and AML (+17 pp) in children. Image:Summary/Conclusion: The increase in incidence and the improvement in survival during the period 2004-2018 can be partly explained by the diagnostic and therapeutic innovations over the 2 last decades. This real-world population-based study provides useful information on patients usually excluded from clinical trials (those with advanced age, comorbidities, other malignancies).Older patients showed the greatest improvement over time. However, this study also highlights entities that need more attention for improvement, such as AML and MDS.